1. Field of the Invention
The present invention relates to a semiconductor device including a trench gate MOSFET and a method of manufacturing the same.
2. Description of Related Art
As an example of a trench gate MOSFET, a semiconductor device according to Patent Document 1 (Japanese Unexamined Patent Publication No. 2010-62477), for example, includes an n−-type first base layer provided with a gate trench, a gate insulating film formed on the inner surface of the gate trench, a gate electrode charged into the gate insulating film, an interlayer dielectric film formed to cover the gate electrode, a p-type second base layer formed on the surface of the n−-type first base layer to be shallower than the bottom surface of the gate trench, an n+-type source layer formed on the surface of the p-type second base layer, a self-aligned contact trench formed into the p-type second base layer through the n+-type source layer, a source electrode connected to the p-type second base layer on the bottom surface of the self-aligned contact trench and connected to the n+-type source layer on the side surface of the self-aligned contact trench, an n+-type drain layer formed on the back surface of the n−-type first base layer, and a drain electrode formed on the n+-type drain layer.